Internal combustion engines, including turbine engines, have fuel injectors or fuel nozzles that inject liquid and/or gaseous fuel for mixing with compressed air and subsequent combustion in a combustion chamber of the engine. One such fuel injector is discussed in U.S. Patent Application Publication No. 2007/0074518A (“the '518 publication”). The '518 publication discloses a fuel nozzle including a barrel housing connected at one end to an air inlet duct for receiving compressed air, and on the opposing end to a mixing duct for communication of the fuel/air mixture with the combustor of the turbine engine. The fuel injector also includes a central body, a pilot fuel assembly, and a swirler. The central body and the pilot fuel assembly may be disposed radially inward of the barrel housing and aligned along a common axis. The pilot fuel assembly extends within the central body and is configured to inject a pilot stream of pressurized fuel into the combustor to facilitate engine starting, idling, cold operation, and/or lean burn operations of the turbine engine. The swirler is radially disposed between the barrel housing and central body.
The air inlet duct of the fuel injector includes a tubular arrangement configured to axially direct compressed air from the compressor section of the turbine engine into the barrel housing of the fuel injector. Air inlet duct 14 may include a central inlet opening and a flow restrictor located within the central inlet opening at a proximal end of the barrel housing. This flow restrictor (or blocker ring) extends circumferentially around the central inlet opening. The radial distance that the blocker ring protrudes into central inlet opening determines the amount of compressed air received within fuel injector through the air inlet duct. Thus, the size of the blocker ring affects the amount of air that is combusted in the combustor of the engine.